This Mentored Patient-Oriented Research Career Development Award (K23) will enable the candidate, a clinical psychologist, to become an independent researcher in developmental psychopathology, with a focus on family processes among clinically anxious children. The long-term career goal is to apply knowledge from research on the development, maintenance and exacerbation of anxiety in children to improving treatments for this population. Training goals for the Award period are to develop expertise in designing and conducting observational research with anxious youth that incorporates specialized technical training in: 1) microanalytic observational research methods, 2) psychophysiological and behavioral assessment of reactivity and regulation, and 3) sequential data analysis. The research goal for the Award period is to integrate data collected using these different assessment approaches to describe the relationship between child reactivity, regulation, and parent-child interactive behavior. The proposed study involves assessing parent-child interactive behavior, child reactivity, and child emotion regulation in 180 children ages 8-12 years (60 with Obsessive Compulsive Disorder, 60 with non-OCD anxiety disorder, 60 non-clinical controls). Adaptation of existing global and microanalytic observational coding systems of parent-child interactive behavior and child emotional reactivity and regulation are planned. Physiological reactivity (heart rate, respiratory sinus arrhythmia) will also be assessed. The Candidate will complete rigorous training with Ronald Seifer, Ph.D., an expert in developmental psychopathology research, observational assessment of family processes, and biostatistics including sequential analysis. Co-mentors include those with expertise in clinical presentations of, and implications of such work with anxious youth (Henrietta Leonard, M.D.), psychophysiological assessment and integration of these data with behavioral data (Barry Lester, Ph.D., Susan Calkins, Ph.D.), and observational and psychophysiological assessment of emotion regulation (Susan Calkins, Ph.D.). With such specialized training, the candidate will be prepared in future research to examine child temperament and family influences on the development, maintenance and exacerbation of anxiety in youth. Future treatment development work will also be informed by the results of this project.